from app.causal_explainer import CausalExplainer
from fastapi import APIRouter, Depends, Request, BackgroundTasks, HTTPException
from pydantic import BaseModel
from typing import Optional
from enum import Enum
import time
import json

# ===== USAGE TRACKER IMPORTS =====
from app.core.usage_tracker import enforce_quota, UsageRecord, tracker


class HealingAction(str, Enum):
    NO_ACTION = "no_action"
    RESTART_CONTAINER = "restart_container"
    SCALE_OUT = "scale_out"
    ROLLBACK = "rollback"
    CIRCUIT_BREAKER = "circuit_breaker"
    TRAFFIC_SHIFT = "traffic_shift"
    ALERT_TEAM = "alert_team"


class ReliabilityEvent(BaseModel):
    component: str
    latency_p99: float
    error_rate: float
    service_mesh: str = "default"
    cpu_util: Optional[float] = None
    memory_util: Optional[float] = None


router = APIRouter()
incident_history = []


@router.post("/report_incident")
async def report_incident(event: ReliabilityEvent):
    incident_history.append(event.dict())
    return {"status": "recorded"}


@router.post("/v1/incidents/evaluate")
async def evaluate_incident(
    request: Request,
    event: ReliabilityEvent,
    background_tasks: BackgroundTasks,
    quota: dict = Depends(enforce_quota)
):
    start_time = time.time()
    api_key = quota["api_key"]
    tier = quota["tier"]
    response_data = None
    error_msg = None

    try:
        # Simple risk score (heuristic)
        risk_score = min(1.0, (event.latency_p99 / 1000.0) * 0.7 + event.error_rate * 0.3)

        if event.latency_p99 > 500 or event.error_rate > 0.15:
            optimal_action = HealingAction.RESTART_CONTAINER
        else:
            optimal_action = HealingAction.NO_ACTION

        current_state = {
            "latency": event.latency_p99,
            "error_rate": event.error_rate,
            "last_action": {"action_type": "no_action"}
        }
        proposed_action = {"action_type": optimal_action.value, "params": {}}
        ce = CausalExplainer()
        causal_exp = ce.explain_healing_intent(proposed_action, current_state, "latency")

        healing_intent = {
            "action": optimal_action.value,
            "component": event.component,
            "parameters": proposed_action["params"],
            "justification": f"Causal: {causal_exp.explanation_text}",
            "confidence": 0.85,
            "risk_score": risk_score,
            "status": "oss_advisory_only"
        }

        response_data = {
            "healing_intent": healing_intent,
            "causal_explanation": {
                "factual_outcome": causal_exp.factual_outcome,
                "counterfactual_outcome": causal_exp.counterfactual_outcome,
                "effect": causal_exp.effect,
                "explanation_text": causal_exp.explanation_text,
                "is_model_based": causal_exp.is_model_based,
                "warnings": causal_exp.warnings
            },
            "utility_decision": {
                "best_action": optimal_action.value,
                "expected_utility": 0.5,
                "explanation": "Heuristic decision based on latency/error thresholds"
            }
        }

        # Asynchronous usage logging
        if tracker:
            record = UsageRecord(
                api_key=api_key,
                tier=tier,
                timestamp=time.time(),
                endpoint="/v1/incidents/evaluate",
                request_body=event.dict(),
                response=response_data,
                processing_ms=(time.time() - start_time) * 1000,
            )
            await tracker.increment_usage_async(record, background_tasks)

        return response_data

    except HTTPException:
        raise
    except Exception as e:
        error_msg = str(e)
        # Log failure in background
        if tracker:
            record = UsageRecord(
                api_key=api_key,
                tier=tier,
                timestamp=time.time(),
                endpoint="/v1/incidents/evaluate",
                request_body=event.dict(),
                error=error_msg,
                processing_ms=(time.time() - start_time) * 1000,
            )
            await tracker.increment_usage_async(record, background_tasks)
        raise HTTPException(status_code=500, detail=error_msg)